I just built 5 swarm traps out of old fence panel wood. Because there are places in the wood (knots, cracks, etc..) that prevent the individual boards from being tight, there are cracks and crevices that let some light in. How dark and tight does it need to be inside? I think I have the right size of boxes. They hold 6-7 frames. If there is too many cracks, would "great stuff" work to seal them up? Just wondering. I have hung 3 already and don't want to miss out on a picky, passing swarm. Here is a pic of probably the "crackiest" of the 5. Thanks!